The widow of the ex-KGB agent-turned-Kremlin critic who was mysteriously poisoned four years ago said classified cables released by WikiLeaks prove Russian leader Vladimir Putin ordered his murder.

“There is some satisfaction in seeing what we have known to be true documented so officially, and I would add brutally by being so matter of fact in its description,” said Marina Litvinenko, widow of Alexander Litvinenko.

“For years we have been trying to get the authorities in the West to view my husband’s murder as a state-sponsored crime,” she told The Guardian. “Now it appears they knew it all along.”

Senior US diplomat Daniel Fried said that, given “Putin’s attention to detail,” it was improbable that he was ignorant of the plot to poison Litvinenko with a fatal dose of radioactive polonium, according to a 2006 cable.

On his deathbed in London, Litvinenko, a restless critic of Russia, called his poisoning “Vladimir Putin’s work.”

Among the other WikiLeaks revelations yesterday:

* US diplomats reported that not only are Putin and Italian PM Silvio Berlusconi BFFs, but that Berlusconi himself gets “a percentage of profits from any pipelines developed by Gazprom,” the Russian oil company.

* The CIA drafted a “wish list” of foreign dignitaries, including UN Secretary-General Ban Ki-moon, that State Department officials were ordered to spy on, including obtaining access to e-mails and biometric data.

* Cables painted an even bleaker picture of government corruption in Afghanistan with Ambassador Karl Eikenberry writing the “key government officials are themselves corrupt.”

The Litvinenko cable was based on a meeting between Fried and Maurice Gourdault-Montagne, a French presidential national security adviser.

“Fried, noting Putin’s attention to detail, questioned whether rogue security elements could operate, in the UK no less, without Putin’s knowledge,” the classified cable states. “Describing the current atmosphere as strange, he described the Russians as increasingly self-confident, to the point of arrogance.”

Kremlin spokesman Dmitry Peskov countered in a BBC interview that US diplomats have a “perverted understanding of reality.”

Litvinenko mysteriously fell fatally ill while living as an exile in London in November 2006 after meeting with two former Russian intelligence agents.